A mad scientist uses captured criminals as experiments for his study on "the criminal mind" aboard his private ship.
| Actor | Role |
|---|---|
 Lyle TalbotLt. Bob Bennett | Lt. Bob Bennett |
 Irving PichelDr. Herbert Stander | Dr. Herbert Stander |
 Julie BishopJoan Martel | Joan Martel |
 Sheila BromleyPoison Mary Slavish | Poison Mary Slavish |
 Anthony AverillDirk - Stander's Aide | Dirk - Stander's Aide |
 Russell HoptonHarry 'The Carver' Bogard | Harry 'The Carver' Bogard |
 Julian MadisonPaul - Stander's Aide | Paul - Stander's Aide |
| EEddie HoldenOle Olson | Ole Olson |
 Wheeler OakmanJohn Ritter | John Ritter |
 Stanley BlystoneCapt. Mike Briggs | Capt. Mike Briggs |
| LLeander De CordovaEzra Matthews | Ezra Matthews |
| DDemetrius AlexisSteve Murano | Steve Murano |
 Skelton KnaggsJesse Bixel | Jesse Bixel |
 Carleton YoungReporter | Reporter |
| WWilliam N. ChapmanBill | Bill |
| JJack GardnerReporter | Reporter |
 Adia KuznetzoffAdolph Krantz | Adolph Krantz |
| BBert LeBaronSailor | Sailor |
| FFred WaltonDr. Beemish | Dr. Beemish |